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4K resolution
From Wikipedia, the free encyclopedia
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4K resolution refers to a horizontal display resolution of approximately 4,000 pixels.[1] Digital television and digital cinematography commonly use several different 4K resolutions. In television and consumer media, 3840 × 2160 (4K UHD) is the dominant 4K standard, whereas the movie projection industry uses 4096 × 2160 (DCI 4K).

The 4K television market share increased as prices fell dramatically during 2014[2] and 2015.

Comparison of common broadcast resolutions

Comparison of common display resolutions

Contents
1 4K standards and terminology
1.1 DCI Digital Cinema System Specification
1.2 SMPTE UHDTV standard
1.3 ITU-R UHDTV standard
1.4 CEA Ultra HD
1.5 2160p resolution
1.5.1 M+ or RGBW TV controversy
1.6 CinemaWide 4K
2 Adoption
2.1 ATSC
2.2 DVB
2.3 Video streaming
2.4 Mobile phone cameras
3 History
3.1 Home video projection
4 Broadcasting
5 Resolutions
5.1 3840 × 2160
5.2 4096 × 2160
5.3 Other 4K resolutions
6 Recording
6.1 Detail benefit
6.2 Chroma subsampling
6.3 Bit rates
7 See also
8 References
9 External links
9.1 Articles
9.2 Official sites of NHK
9.3 Video
4K standards and terminology
The term "4K" is generic and refers to any resolution with a horizontal pixel count of approximately 4,000.[3]: 2 Several different 4K resolutions have been standardized by various organizations.

The terms "4K" and "Ultra HD" are used more widely in marketing than "2160p". While typically referring to motion pictures, some digital camera vendors have used the term "4K photo" for still photographs, making it appear like an especially high resolution even though 3840×2160 pixels equal approximately 8.3 megapixels, which is not considered to be especially high for still photographs.[4]

DCI Digital Cinema System Specification

Comparison of DCI and UHD resolutions
In 2005, Digital Cinema Initiatives (DCI), a prominent standards organization in the cinema industry, published the Digital Cinema System Specification. This specification establishes standardized 2K and 4K container formats for digital cinema production, with resolutions of 2048 × 1080 and 4096 × 2160 respectively.[5]: §4.3.1 The resolution of the video content inside follows the SMPTE 428-1 standard,[5]: §3.2.1 which establishes the following resolutions for a 4K distribution:[6]: 6

4096 × 2160 (full frame, 256∶135 or ≈1.90∶1 aspect ratio)
3996 × 2160 (flat crop, 1.85∶1 aspect ratio)
4096 × 1716 (CinemaScope crop, ≈2.39∶1 aspect ratio)
2K distributions can have a frame rate of either 24 or 48 FPS, while 4K distributions must have a frame rate of 24 FPS.[5]: §3.1.4.2 Some articles claim that the terms "2K" and "4K" were coined by DCI and refer exclusively to the 2K and 4K formats defined in the DCI standard.[7] However, usage of these terms in the cinema industry predates the publication of the DCI standard,[8][9][10][11] and they are generally understood as casual terms for any resolution approximately 2000 or 4000 pixels in width, rather than names for specific resolutions.[3]: 2 [12]: 109

SMPTE UHDTV standard
In 2007, the Society of Motion Picture and Television Engineers published SMPTE ST 2036-1, which defines parameters for two UHDTV systems called UHDTV1 and UHDTV2.[13][14] The standard defines the following characteristics for these systems:

A resolution of 3840 × 2160 (UHDTV1) or 7680 × 4320 (UHDTV2)[14]: §5.2
Square (1∶1) pixels, for an overall image aspect ratio of 16∶9[14]: §5.1
A framerate of 23.976, 24, 25, 29.97, 30, 50, 59.94, 60, 100, 119.88, or 120 Hz with progressive scan[14]: §1.2
RGB, Y′CBCR 4:4:4, 4:2:2, or 4:2:0 pixel encoding[14]: §7.7
10 bpc (30 bit/px) or 12 bpc (36 bit/px) color depth[14]: §1.2
Colorimetry characteristics as defined in the standard, including color primaries, quantization parameters, and the electro-optical transfer function. These are the same characteristics later standardized in ITU-R BT.2020. UHDTV1 systems are permitted to use BT.709 color primaries up to 60 Hz.[14]: §6.2
ITU-R UHDTV standard
In 2012, the International Telecommunication Union, Radiocommunication Sector published Recommendation ITU-R BT.2020, also known as the Ultra High Definition Television (UHDTV) standard.[15] It adopts the same image parameters defined in SMPTE ST 2036–1.[16]

Although the UHDTV standard does not define any official names for the formats it defines, ITU typically uses the terms "4K", "4K UHD", or "4K UHDTV" to refer to the 3840 × 2160 system in public announcements and press releases ("8K" for the 7680 × 4320 system).[17] In some of ITU's other standards documents, the terms "UHDTV1" and "UHDTV2" are used as shorthand.[18]

CEA Ultra HD
In October 2012, the Consumer Electronics Association (CEA) announced their definition of the term Ultra High-Definition (or Ultra HD) for use with marketing consumer display devices.[19] CEA defines an Ultra HD product as a TV, monitor, or projector with the following characteristics:[20]

A resolution of 3840 × 2160 or larger
An aspect ratio of 1.77∶1 (16∶9) or wider
Support for color depth of 8 bpc (24 bit/px) or higher
At least one HDMI input capable of supporting 3840 × 2160 at 24, 30, and 60 Hz progressive scan (though not necessarily with RGB / Y′CBCR 4:4:4 color), and HDCP 2.2
Capable of processing images according to the color space defined in ITU-R BT.709
Capable of upscaling HD content (i.e. 720p / 1080p)
The CEA definition does allow manufacturers to use other terms—such as 4K—alongside the Ultra HD logo.[3]: 9 Since the resolution in CEA's definition is only a minimum requirement, displays with higher resolutions such as 4096 × 2160 or 5120 × 2880 also qualify as "Ultra HD" displays, provided they meet the other requirements.

2160p resolution
Some 4K resolutions, like 3840 × 2160, are often casually referred to as 2160p.[21][22][23] This name follows from the previous naming convention used by HDTV and SDTV formats, which refer to a format by the number of pixels/lines along the vertical axis (such as "1080p" for 1920 × 1080 progressive scan, or "480i" for the 480-line interlaced SDTV formats) rather than the horizontal pixel count (≈4000 or "4K" for 3840 × 2160).

The term "2160p" could be applied to any format with a height of 2160 pixels, but it is most commonly used in reference to the 4K UHDTV resolution of 3840 × 2160 due to its association with the well-known 720p and 1080p HDTV formats. Although 3840 × 2160 is both a 4K resolution and a 2160p resolution, these terms cannot always be used interchangeably since not all 4K resolutions are 2160 pixels tall, and not all 2160p resolutions are ≈4000 pixels wide. However, some companies have begun using the term "4K" to describe devices with support for a 2160p resolution, even if it is not close to 4000 pixels wide. For example, many "4K" dash cams only support a resolution of 2880 × 2160 (4∶3);[24][25] although this is a 2160p resolution, it is not a 4K resolution. Conversely, Samsung released a 5120 × 2160 (64∶27) TV, but marketed it as a "4K" TV despite its 5K-class resolution.[26][27]

M+ or RGBW TV controversy
In 2015, LG Display announced the implementation of a new technology called M+ which is the addition of white subpixel along with the regular RGB dots in their IPS panel technology.[28] The media and internet users later called this "RGBW" TVs because of the white sub pixel.

Most of the new M+ technology was employed on 4K TV sets which led to a controversy after tests showed that the addition of a white sub pixel replacing the traditional RGB structure would reduce the resolution by around 25%. After tests done by Intertek in which the technical aspects of LG M+ TVs were analyzed and they concluded that "the addressable resolution display is 2,880 X 2,160 for each red, green, blue", in other words, the LG TVs were technically 2.8K as it became known in the controversy.[29][30] Although LG Display has developed this technology for use in notebook display, outdoor and smartphones, it is more popular in the TV market due to the supposed 4K UHD marketed resolution but still being incapable of achieving true 4K UHD resolution as defined by the CTA as 3840x2160 active pixels with 8-bit per color. This negatively impacts the rendering of text, making it a bit fuzzier, which is especially noticeable when a TV is used as a PC monitor.[31][32][33][34][35]

CinemaWide 4K
In 2019, Sony was granted the CinemaWide trademark by the European Union Intellectual Property Office (EUIPO), in which the trademark covers 'Class 9' electronic devices, including smartphones.[36] According to Sony and SID,[37] the standard defines a CinemaWide 4K product with the following characteristics:

A resolution of 3840 × 1644 or larger
An aspect ratio of 21∶9

From Wikipedia, the free encyclopedia
Jump to navigationJump to search
4K resolution refers to a horizontal display resolution of approximately 4,000 pixels.[1] Digital television and digital cinematography commonly use several different 4K resolutions. In television and consumer media, 3840 × 2160 (4K UHD) is the dominant 4K standard, whereas the movie projection industry uses 4096 × 2160 (DCI 4K).

The 4K television market share increased as prices fell dramatically during 2014[2] and 2015.

Comparison of common broadcast resolutions

Comparison of common display resolutions

Contents
1 4K standards and terminology
1.1 DCI Digital Cinema System Specification
1.2 SMPTE UHDTV standard
1.3 ITU-R UHDTV standard
1.4 CEA Ultra HD
1.5 2160p resolution
1.5.1 M+ or RGBW TV controversy
1.6 CinemaWide 4K
2 Adoption
2.1 ATSC
2.2 DVB
2.3 Video streaming
2.4 Mobile phone cameras
3 History
3.1 Home video projection
4 Broadcasting
5 Resolutions
5.1 3840 × 2160
5.2 4096 × 2160
5.3 Other 4K resolutions
6 Recording
6.1 Detail benefit
6.2 Chroma subsampling
6.3 Bit rates
7 See also
8 References
9 External links
9.1 Articles
9.2 Official sites of NHK
9.3 Video
4K standards and terminology
The term "4K" is generic and refers to any resolution with a horizontal pixel count of approximately 4,000.[3]: 2 Several different 4K resolutions have been standardized by various organizations.

The terms "4K" and "Ultra HD" are used more widely in marketing than "2160p". While typically referring to motion pictures, some digital camera vendors have used the term "4K photo" for still photographs, making it appear like an especially high resolution even though 3840×2160 pixels equal approximately 8.3 megapixels, which is not considered to be especially high for still photographs.[4]

DCI Digital Cinema System Specification

Comparison of DCI and UHD resolutions
In 2005, Digital Cinema Initiatives (DCI), a prominent standards organization in the cinema industry, published the Digital Cinema System Specification. This specification establishes standardized 2K and 4K container formats for digital cinema production, with resolutions of 2048 × 1080 and 4096 × 2160 respectively.[5]: §4.3.1 The resolution of the video content inside follows the SMPTE 428-1 standard,[5]: §3.2.1 which establishes the following resolutions for a 4K distribution:[6]: 6

4096 × 2160 (full frame, 256∶135 or ≈1.90∶1 aspect ratio)
3996 × 2160 (flat crop, 1.85∶1 aspect ratio)
4096 × 1716 (CinemaScope crop, ≈2.39∶1 aspect ratio)
2K distributions can have a frame rate of either 24 or 48 FPS, while 4K distributions must have a frame rate of 24 FPS.[5]: §3.1.4.2 Some articles claim that the terms "2K" and "4K" were coined by DCI and refer exclusively to the 2K and 4K formats defined in the DCI standard.[7] However, usage of these terms in the cinema industry predates the publication of the DCI standard,[8][9][10][11] and they are generally understood as casual terms for any resolution approximately 2000 or 4000 pixels in width, rather than names for specific resolutions.[3]: 2 [12]: 109

SMPTE UHDTV standard
In 2007, the Society of Motion Picture and Television Engineers published SMPTE ST 2036-1, which defines parameters for two UHDTV systems called UHDTV1 and UHDTV2.[13][14] The standard defines the following characteristics for these systems:

A resolution of 3840 × 2160 (UHDTV1) or 7680 × 4320 (UHDTV2)[14]: §5.2
Square (1∶1) pixels, for an overall image aspect ratio of 16∶9[14]: §5.1
A framerate of 23.976, 24, 25, 29.97, 30, 50, 59.94, 60, 100, 119.88, or 120 Hz with progressive scan[14]: §1.2
RGB, Y′CBCR 4:4:4, 4:2:2, or 4:2:0 pixel encoding[14]: §7.7
10 bpc (30 bit/px) or 12 bpc (36 bit/px) color depth[14]: §1.2
Colorimetry characteristics as defined in the standard, including color primaries, quantization parameters, and the electro-optical transfer function. These are the same characteristics later standardized in ITU-R BT.2020. UHDTV1 systems are permitted to use BT.709 color primaries up to 60 Hz.[14]: §6.2
ITU-R UHDTV standard
In 2012, the International Telecommunication Union, Radiocommunication Sector published Recommendation ITU-R BT.2020, also known as the Ultra High Definition Television (UHDTV) standard.[15] It adopts the same image parameters defined in SMPTE ST 2036–1.[16]

Although the UHDTV standard does not define any official names for the formats it defines, ITU typically uses the terms "4K", "4K UHD", or "4K UHDTV" to refer to the 3840 × 2160 system in public announcements and press releases ("8K" for the 7680 × 4320 system).[17] In some of ITU's other standards documents, the terms "UHDTV1" and "UHDTV2" are used as shorthand.[18]

CEA Ultra HD
In October 2012, the Consumer Electronics Association (CEA) announced their definition of the term Ultra High-Definition (or Ultra HD) for use with marketing consumer display devices.[19] CEA defines an Ultra HD product as a TV, monitor, or projector with the following characteristics:[20]

A resolution of 3840 × 2160 or larger
An aspect ratio of 1.77∶1 (16∶9) or wider
Support for color depth of 8 bpc (24 bit/px) or higher
At least one HDMI input capable of supporting 3840 × 2160 at 24, 30, and 60 Hz progressive scan (though not necessarily with RGB / Y′CBCR 4:4:4 color), and HDCP 2.2
Capable of processing images according to the color space defined in ITU-R BT.709
Capable of upscaling HD content (i.e. 720p / 1080p)
The CEA definition does allow manufacturers to use other terms—such as 4K—alongside the Ultra HD logo.[3]: 9 Since the resolution in CEA's definition is only a minimum requirement, displays with higher resolutions such as 4096 × 2160 or 5120 × 2880 also qualify as "Ultra HD" displays, provided they meet the other requirements.

2160p resolution
Some 4K resolutions, like 3840 × 2160, are often casually referred to as 2160p.[21][22][23] This name follows from the previous naming convention used by HDTV and SDTV formats, which refer to a format by the number of pixels/lines along the vertical axis (such as "1080p" for 1920 × 1080 progressive scan, or "480i" for the 480-line interlaced SDTV formats) rather than the horizontal pixel count (≈4000 or "4K" for 3840 × 2160).

The term "2160p" could be applied to any format with a height of 2160 pixels, but it is most commonly used in reference to the 4K UHDTV resolution of 3840 × 2160 due to its association with the well-known 720p and 1080p HDTV formats. Although 3840 × 2160 is both a 4K resolution and a 2160p resolution, these terms cannot always be used interchangeably since not all 4K resolutions are 2160 pixels tall, and not all 2160p resolutions are ≈4000 pixels wide. However, some companies have begun using the term "4K" to describe devices with support for a 2160p resolution, even if it is not close to 4000 pixels wide. For example, many "4K" dash cams only support a resolution of 2880 × 2160 (4∶3);[24][25] although this is a 2160p resolution, it is not a 4K resolution. Conversely, Samsung released a 5120 × 2160 (64∶27) TV, but marketed it as a "4K" TV despite its 5K-class resolution.[26][27]

M+ or RGBW TV controversy
In 2015, LG Display announced the implementation of a new technology called M+ which is the addition of white subpixel along with the regular RGB dots in their IPS panel technology.[28] The media and internet users later called this "RGBW" TVs because of the white sub pixel.

Most of the new M+ technology was employed on 4K TV sets which led to a controversy after tests showed that the addition of a white sub pixel replacing the traditional RGB structure would reduce the resolution by around 25%. After tests done by Intertek in which the technical aspects of LG M+ TVs were analyzed and they concluded that "the addressable resolution display is 2,880 X 2,160 for each red, green, blue", in other words, the LG TVs were technically 2.8K as it became known in the controversy.[29][30] Although LG Display has developed this technology for use in notebook display, outdoor and smartphones, it is more popular in the TV market due to the supposed 4K UHD marketed resolution but still being incapable of achieving true 4K UHD resolution as defined by the CTA as 3840x2160 active pixels with 8-bit per color. This negatively impacts the rendering of text, making it a bit fuzzier, which is especially noticeable when a TV is used as a PC monitor.[31][32][33][34][35]

CinemaWide 4K
In 2019, Sony was granted the CinemaWide trademark by the European Union Intellectual Property Office (EUIPO), in which the trademark covers 'Class 9' electronic devices, including smartphones.[36] According to Sony and SID,[37] the standard defines a CinemaWide 4K product with the following characteristics:

A resolution of 3840 × 1644 or larger
An aspect ratio of 21∶9
Capable of playing back 4K resolution video (2160p) in an aspect ratio of 21∶9
Capable of upscaling non-4K content (i.e. 720p / 1080p)[38]
Sony Xperia smartphones are the most widely known products that equipped with CinemaWide 4K display, such as Xperia 1, Xperia 1 II and Xperia 1 III.

Adoption
Video sharing website YouTube and the television industry have adopted 3840 × 2160 as their 4K standard.[39][40] As of 2014, 4K content from major broadcasters remained limited.[41] On April 11, 2013, Bulb TV created by Canadian serial entrepreneur Evan Kosiner became the first broadcaster to provide a 4K linear channel and VOD content to cable and satellite companies in North America.[42][43][44][45] The channel is licensed by the Canadian Radio-Television and Telecommunications Commission to provide educational content.[46] However, 4K content is becoming more widely available online[when?] including on Apple TV, YouTube, Netflix, Hulu, and Amazon.[47][48] By 2013, some UHDTV models were available to general consumers in the range of US$600.[49][50] As of 2015, prices on smaller computer and television panels had dropped below US$400.[51]

ATSC
On March 26, 2013, the Advanced Television Systems Committee announced new proposals of a new standard called ATSC 3.0 which would implement UHD broadcasts at resolutions of up to 3840 × 2160 or 7680 × 4320.[52][53][54][55] The standard would also include framerates of up to 120 Hz, HEVC encoding, wide color gamut, as well as high dynamic range.[56][57][58]

DVB
In 2014, the Digital Video Broadcasting Project released a new set of standards intended to guide the implementation of high resolution content in broadcast television. Dubbed DVB-UHDTV, it establishes two standards, known as UHD-1 (for 4K content) and UHD-2 (for 8K content). These standards use resolutions of 3840 × 2160 and 7680 × 4320 respectively, with framerates of up to 60 Hz, color depth up to 10 bpc (30 bit/px), and HEVC encoding for transmission.[59] DVB is currently focusing on the implementation of the UHD-1 standard.[60]

DVB finalized UHD-1 Phase 2 in 2016, with the introduction of service by broadcasters expected in 2017. UHD-1 Phase 2 adds features such as high dynamic range (using HLG and PQ at 10 or 12 bits), wide color gamut (BT. 2020/2100 colorimetry), and high frame rate (up to 120 Hz).[61][60]

Video streaming
YouTube, since 2010,[62] and Vimeo allow a maximum upload resolution of 4096 × 3072 pixels (12.6 megapixels, aspect ratio 4:3).[63][64] Vimeo's 4K content is currently limited to mostly nature documentaries and tech coverage.[65][66]

High Efficiency Video Coding (HEVC or H.265) should allow streaming 4K content with a bandwidth of 20 to 30 Mbit/s.[67]

In January 2014, Naughty America launched the first adult video service streaming in 4K.[68][69]

Mobile phone cameras
See also: Category: Mobile phones with 4K video recording